Staudey Have you installed xdg-desktop-portal-gtk?
I've also had a lot of problems with flats and some native apps not launching when certain buttons are pushed. More stuff lately than I can keep track of. Just really weird. I had xdg-portal problems months ago that got semi-cured with an update.
So I installed the gtk package last night and will monitor if things change in the next week. My question to you is
xdg-desktop-portal-gtk for Budgie as well as Gnome? I think the answer is yes, but unsure. Thanks.
MetaNorm sorry for getting sidetracked on your post